code: def test_masking(self):
      a = named_array.NamedNumpyArray(
          [[1, 2, 3, 4], [5, 6, 7, 8]], [None, list("abcd")]
      )
      self.assertArrayEqual(a[a > 2], [3, 4, 5, 6, 7, 8])
      self.assertArrayEqual(a[a < 4], [1, 2, 3])
      self.assertArrayEqual(a[a % 2 == 0], [2, 4, 6, 8])
      self.assertArrayEqual(a[a % 3 == 0], [3, 6])
  
imports: import collections
  import enum
  import pickle
  from absl.testing import absltest
  from absl.testing import parameterized
  import numpy
  from pysc2.lib import named_array
label_desc: Use image node_id 7 for calling the NamedArrayTest obj's underlying member method code with example usage: obj.test_masking() without return types